TM 9-4910-663-12
b.
Control Panel.
(1) EXTERNAL FIELD EXCITER AC SYSTEM Switch (S31, fig 2-2).
This switch is used in conjunction with the MANUAL position of FIELD
CIRCUIT switch (S32, fig 2-2). When set to ON, it selects external
exciter control for the field of the ac system undergoing test.
(2) GENERATOR FIELD Switch (S37, fig 2-2). This switch provides
means for selecting either internal or external grounding for the
field of the unit undergoing test.
(3) POLARITY REVERSING Switch (S7, fig 2-2). This switch pro-
vides means for actuating relays in the test stand as required to
accommodate generators with negative or positive grounds.
(4) FIELD CIRCUIT Switch (S32, fig 2-2). This switch selects
the type of control of field current for the unit undergoing test. In
the MANUAL position, field current is adjusted by means of the test
stand rheostat (R26, R27, fig 2-2). In the REGULATOR position, field
current is regulated by an external regulator.
(5) 6 VOLT Indicator Light (DS4, fig 2-2). This 6 VOLT indica-
tor light will illuminate whenever the BATTERY CURRENT SELECTOR switch
(S6, fig 2-2) is positioned to the 6V position.
(6) CIRCUIT BREAKERS (CB2 thru CB9 and CB11, fig 2-2). These
circuits of the test stand, as follows:
(a) CB7 controls application of ac power to the dc variable
volts circuits, and provides protection for the ac power circuits.
(b) CB2 controls application of ac power to all test stand
circuits except the varidrive and blower, and provides protection for
the 110-volt control circuits of the test stand.
(c) CB9 controls application of dc output voltage of the dc
variable volts circuit to the test circuits, and provides protection
for these dc output circuits.
(d) CB5 controls application of ac power to the relay control
circuits, and provides protection to the dc relay control power cir-
cuits of the test stand.
(e) CB3 controls application of ac power to the blower motor
(4, fig 4-4), and provides protection to the blower motor.
circuits, and provides protection for these ac power circuits.
2-6